Hygrometer for regulating humidifying and heating systems.



S. W. GRAMER & W. B. HODGE. HYGROMETBR FOR REGULATING HUMIDIFYING AND HEATING SYSTEMS APPLICATION FILED DBO.21., 190'].

Patented Apr. 26, 1910.

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UNITED STATES STUART W. CRAMER nun WILLIAM B. Hones, or cn-a'anor'rn, earn HODGE AssIeNon T0 sarn oaAM-nn.

PATENT oFFIoE.

Specification of Letters I'atent.

Patented Apr. 26, 1910.

Application filed December .21, 1907. Serial No. 407,521.

T 0 all whom it may concern:

Be itknown that we, STUART W. CRAMER and WILLIAM B. Hones, citizens of the United States, residing at Charlotte, in-the county of Mecklenburg and State of North Carolina, have invented certain new and useful Improvements 'in Hygrometers for Regulating Humidifying and Heating Systems; and we do hereby declare the ollowingto be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it 'appertains to make and use the same.

Our invention relates to instruments for indicating and regulating the degree of moisture in the atmosphere in a factory or other building, and in separate rooms thereof. v

The invention consists in certain improvements in construction of the device shown in Patent 856,944, bearing date of June 11, 1907, which improvements will be fully disclosed in the following specification and claims.

I represents a front elevation of our improved instrument. Fig. 2 a like view of a modification of the'same, andFig. 3 a diagrammatic view of the electrical connections.

Reference being had to the drawings and the designating characters thereon, the numerall indicates one bulb of a differential thermometer, and 2 the other bulb, the bulbs being connected by stem 3-4, bent in U form and in thebend 5 of which is a liquid conductor, 6, consistin of mercury or other suitablematerial capa 1c of moving up anddown the inner legs 7, 8 of the stem, .as differences in temperature occur in bulbs 1 and 2. Within each of said [inner legs 7, 8 is a fine wire 9 emerging at points 10 and 11',

a portion of this conductor always being' short circuited by conductor 6. To points 10 and 11 are connected auxiliary resistances -12 and 13, in this particular' ,case' joined in the form of Wheatstone bridge. Also con-- nected to the points 10 and 11 are the terminals 14, 15 of current supply wires connected to a battery 15' of the two resistance coils 12 and 13 and to the liquid conductor 6 are connected the ter- 17 of a suitable device 18 for minals 16 This current indicating electric current.

indicator is arranged to open and close an and to the junctionauxiliary electrical circuit, thereby actuating a valve controlling the admission of moisture to the compartment. P and P auxiliary circuit, shown diagrammatically in Fig. 3 where 15 represents an auxiliary ture controlling valve.

19 indicates wicking covering the bulb 2 and arranged to be-kept moistened by water in a receptacle 20 or bulb 2 can be supplied with moisture by any other well known means.

In Fig. 2, the bend 5 is provided with an auxiliary stem 21 having a chamber 22 containing a liquid conductor 6 capable of changlng volume under diiferences in temperature.

The lengths of free wire between 10 and p 6, and 11 and 6, depend upon the difference in temperature between bulbs 1 and 2, and as this difference in temperature changes, the resistance in these two arms will vary. The Wheatstone bridge being balanced at any predetermined 'dilfere'nce in temperature, an increase or decrease in this difference will disturb the balance and cause a current to flow through the current indicator 18.

It is obvious that there are other electrical connections which can be employed fore do not limit ourselves to the exact deence to actuating a current indicatin baltion, what we claim is- 1. A hygrometer comprising a differential vthermometer having a plurality of legs, inean's for supplying moisture to one of the egs, circuit through each leg; in combination with a; source of electrical energy, and means for balancing'the resistances of said legs.

2'. A 'hygrometer comprising a thermometer having a plurality of legs, means for supplying moisture to one of the legs, an electrical conductor in each leg, a fluid conductor connecting each leg, and means for indicating diiferences in resistances of the exposed portions of said conductors in said legs.

NQRTH CARGLINA;

to accomplish this same result. We therev tails set forth, as this invention has referanced Wheatstone bridge arms in 2. (hi-- and means, for completing an electric represent terminals for connection to this" sourceof electrical energy and V the mois- Having'thus fully described our invendifferential I emcee 3. A hygrometer comprising a difierential means consisting of an electro magnetic l0 thermometer having a plurality of '-le s device. 1 l a means for suppl ing moisture to one of t e In testimony whereof we aifix our signalegs, an electrica conductor in each leg, and tures, in presence of two witnesses. v

STUART W. ORAMER.

a. fluid conductor connecting each leg; in

combination with a source of electrical WILLIAM B. HODGE. energy, and means for indicating difierences Witnesses: in resistances of the exposed portions of said Roger. I. DALTON, Jr.,

conductors in said legs, said indicating JNO. C. WATSON. 

